With recent advances in medical device technology, there has been a growth in the use of minimally invasive surgical techniques for both diagnostic and therapeutic applications by cardiologists and radiologists. For some classes of vascular procedure, they have become the treatment of choice over conventional surgery. With a minimally invasive procedure, it is often necessary to gain access to the blood vessels in order to deliver various medical devices into the vasculature such as wires, balloon catheters and other medical devices in order to treat a disease.
A commonly used procedure with which to gain access to the vascular system for minimally invasive surgery is known as the Seldinger technique. This technique involves using a small gauge hollow needle to puncture the skin and to enter the desired blood vessel. Then, a small guidewire is introduced through the lumen of the needle into the blood vessel and the needle is removed, leaving the wire in place. An introducer sheath with dilator is inserted over the guidewire and pushed through the puncture into the vessel, opening a hole in the vessel wall by forcing the sides of the puncture laterally apart to accommodate the introducer sheath in the opening. The dilator is removed and the introducer sheath, which usually contains a haemostasis valve to stop bleedback from the blood vessel, is left in place. This provides the access port for delivery of diagnostic and therapeutic catheters and medical devices to the vasculature.
Examples of minimally invasive surgery procedures include angiography, balloon angioplasty and stenting, intravascular imaging and thrombectomy. At the conclusion of the interventional procedure, the medical devices used are removed from the body including the catheters, guidewires and introducer sheaths, and it is necessary to close the puncture in the vessel created at the beginning of the procedure. This is done in order to provide haemostasis and to promote healing of the vessel wall and tissue tract.
One treatment to provide haemostasis at the puncture site post procedure is by applying external manual compression for a period of time to the patient at the site of the puncture. The duration and force required depends on the size and location of the puncture, the patient's anatomy, and the amount of anticoagulation treatment administered to the patient. The time required for the manual compression may be long and this may lead to considerable patient discomfort and extend the time to ambulation and the duration of stay in the hospital. This may increase hospital staff time and the cost of health care for the patient. Often supplemental external compression such as sandbags, body clamps and pneumatic devices are used to promote haemostasis in the vessel wall and tissue tract.
Complications may arise with compressive techniques, as too much pressure may restrict or occlude the blood vessel, potentially leading to ischemia and thrombus formation in the vessel. These techniques can have unpredictable post procedural haemorrhaging requiring additional interventions by the doctors and nurses.
Another known treatment is to employ a wound closure device to facilitate the repair of wounds caused by minimally invasive surgical access of the vasculature of the body. A variety of vascular sealing devices have been developed such as: closure devices which include suture mediated, collagen/gel based and staple devices; and assisted compression devices which include mechanical and pressure-assisted compression devices and topical patches.
However these vascular sealing devices suffer from a number of disadvantages, such as:
It may be necessary to repair a puncture site without having any control on the positioning in the vessel, the size or the shape of the puncture;
These devices may lead to puckering of the vessel wall after deployment, leading to the risk of thrombosis and vessel lumen narrowing;
These devices may leave a permanent implant in the closure site on the vessel wall;
Considerable patient discomfort may be caused during the deployment of the devices;
These devices may require additional dilation of the wound post procedure in order to accommodate the size of a staple/clip delivery system;
It may be difficult to effect good closure if the device is poorly placed and it restricts access options for repairs;
The sealing element may be deployed inside the vessel thereby restricting or occluding blood flow;
The sealing material may contain thrombogenic material, which may form thrombus at the vessel puncture and lead to emboli;
There is a risk of embolisation of the gel or foam material in the blood stream due to inaccurate deployment or migration post delivery to the tissue tract;
Ineffective closure of the puncture wound in the blood vessel may occur as the material is deployed in the tissue tract with an increased risk of haemotoma;
These devices are often designed to leave materials on the inside of the blood vessel, thereby increasing the risk of blood flow restriction or occlusion;
A disk may detach from an anchor element and travel distal to the wound site and cause blood flow restrictions or occlusions, potentially requiring surgical intervention;
There is a risk of haematoma forming in the tissue tract;
There is a risk of haemorrhage due to continued patency of the puncture in the vessel wall;
These devices may require significant manual compression before and during use.
This invention is therefore aimed at providing an improved medical device and method, which will address at least some of the disadvantages encountered in conventional treatments.